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问题:
[单选,材料题] The forty years from the 1930s to the 1970s was an important period
A . in the development of air transportation
B . the earliest passenger flights were successfully operated
C . to make travel easy and pleasant for the passengers
D . to provide different services
E . the shortage of qualified pilots
F . traveling by air was very cheap
参考答案:
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参考解析:
【答案】D
【解析】从第三段可知,在19世纪30年代到70年代,出现了国际航班,远距离运输服务,以及新一代“喷气机”运输和超音速运输服务,由此可知,这一时期开始提供多种不同类型的运输服务。所以本题选D。 |
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